A typical high power, radio frequency (RF) semiconductor device may include one or more input leads, one or more output leads, one or more transistors, bondwires coupling the input lead(s) to the transistor(s), and bondwires coupling the transistor(s) to the output lead(s). The bondwires have significant inductances at high frequencies, and such inductances may be factored into the design of input and output circuits for a device. In some cases, input and output circuits may be contained within the same package that contains the device's transistor(s). More specifically, an in-package, input impedance matching circuit may be coupled between a device's input lead and a control terminal (e.g., the gate) of a transistor, and an in-package, output circuit (e.g., including an output impedance matching circuit and an envelope frequency termination circuit) may be coupled between a current conducting terminal (e.g., the drain) of a transistor and a device's output lead. Each of the input and output circuits may include one or more capacitive and resistive elements, along with the inductances inherent in the sets of bondwires interconnecting those elements with the device's transistor(s) and with the input and output leads. The values of the various components in the input and output circuits affect a number of device performance parameters, including device efficiency, instantaneous signal bandwidth (ISBW), and so on.